Draft control device



NOV. 8, 1938. R w FRANKS 2,135,501

DRAFT CONTROL DEVICE Filed Jan. 28, 1954 Patented Nov. 8, 1938 UNITED STATES PATENT OFFICE 2 Claims.

My invention relates to draft control devices and has for its objectto provide a new and efficient draft control device which will control the draft in the flue and prevent any draft through the 5 furnace when it is not burning and which at the same time will prevent any excessive draft through the fire box when the fire is burning.

A still further object is to provide a draft control device which will save fuel in the quantity used and which will produce greater heat and efficiency from the fuel used in the furnace.

These objects I accomplish with the device illustrated in the accompanying drawing in which similar numerals and letters of reference indicate 15 like parts throughout the several views and as described in the specification forming a part of this application and pointed out in the appended claims.

In the drawing:

Figure 1 is a view of the draft control device showing the draft control plates mounted vertically looking into the device from the end which is attached to the flue pipe of the furnace, with part of the bellows diaphragm cut away.

25 Figure 2 is a side elevation of Figure 1.

Figure 3 is a vertical elevation of Figure 1. Figure 4 is a view of the control removed from the casing.

In the drawing in which I have shown my invention the casing is shown as F; and this casing is attached into open connection with the flue by the flange 35. The end 36 of the casing F is open. The control for this device consists of a centrally mounted control frame work 31 mounted on stud 35 shafts 38 and 39 which extend out through the sides into bearings 40. One shaft 39 extends beyond the bearing and is provided with anadjustable connection block 4| to which a control arm 42 is secured. The arm 42 is in turn connected with a diaphragm 43 by a link 44. This frame work is rotatively balanced by Weights 45 carried on the arm 42 or on other like arms which may be extended from the block 4|. In the casing F across the top thereof I provide a stop angle 46 and a like angle 41 is Secured across the bottom of the casing F both of which are to stop the frame work 31 when it comes to the vertical position. In this frame work I then mount the weighted off center draft responsive closure plates 48 and 49. Each plate is identical except, that they are reversed, one to close each half of the opening through the frame work 31. The plates are made of a sheet of metal 50 having all edges turned up to form a flange therearound and directly across the medial section of each plate on the side enclosed by the flanges I provide a cross bar secured to one side of the plate by a block 52 and to the other side by a changeable weight 53. Onto the bar 5| I then mount an adjustable table weight 54 said weight being provided with a set screw 55 to allow for adjustment thereof and for locking it in a de-' termined position on the bar 5|. The plates are pivotally mounted in the frame work by hearing blocks 56 and 51 being secured to the plates on the same side as the adjustable bar and each block is bored to receive a pivot pin 58, which pin is screwed through the flange of the frame work 31. These blocks 56 and 51 are mounted in a predetermined position nearer one edge of the plates than the other to make the plates mounted off center so that when the frame work is partially rotating the plates will either open or close themselves independent of outside influence other than draft through the casing F. As shown in Figure 3, the arrows a show the direction of opening of the frame work 31.

The bellows diaphragm 43 is provided to operate the framework 31 when it is desired to control this frame work and the position thereof by, or commensurate with, either the pressure of the fuel being fed, or the pressure of the steam in the furnace when the device is in use on a steam boiler type of furnace. Thus when the pressure in the steam boiler is high, the frame work will be held closed or beheld open depending upon which side of the pivot shaft the arm 42 is mounted or upon which side of the casing F the bellows is situated, and it will be obvious that under certain conditions, the bellows will be mounted above the arm 42 instead of under it. As shown in the drawing, Figure 2 shows the link 44 connected to the weight 45 but, this link may be connected in any suitable manner desired, depending upon the requirements, and whether the installation is on a steam boiler furnace, an oil fired furnace, or on a gas fired furnace.

It is to be further understood that in some cases there will be no need of any bellows diaphragm as the device may be used without any such control with equal success.

Having thus described my invention I desire to secure by Letters Patent and claim:

1. In a draft control device, the combination of a casing mounted on the flue of a furnace in open connection therewith but not in the path of travel of the consumed gases; a rotatively counter balanced frame work in said casing; draft responsive plates mounted off center within said frame work; means to adjust the closing pressure of the draft responsive plates to control the amount of opening and. the position of the frame work depending upon the suction through the device and upon the fire conditions in the furnace.

2. In a draft control device, the combination of a casing mounted onto the side and in open connection with the flue of a furnace but, not in the path of travel of the consumed gases; a rotatively counter balanced frame work mounted across said casing; draft responsive closure plates of the draft responsive plates to control the opening and the position of the frame work depending upon the suction through the flue pipe.

ROYE W. IE'RANKS.v 

